Pneumatically operated impact-action self-propelled reversible mechanism

ABSTRACT

There is disclosed a pneumatically operated impact-action selfpropelled reversible mechanism for driving holes in the earth by compacting the soil around the hole being made, comprising a housing having a pointed end and receiving thereinside an impact member delivering successive impacts upon the housing, as this impact member is reciprocated interiorly of this housing in operation of the mechanism under the action of compressed air, the mechanism further including a compressed air supply sleeve connected with an air conduit member and threadedly secured in a nut for axial displacement relative to this nut, when the air conduit member is rotated. According to the invention, the nut, associated with the compressed air supply sleeve, has a plurality of longitudinal oblique slits made therein, these slits defining therebetween a pair of resiliently deformable cantilever members projecting axially beyond the adjacent face end of the nut, the longitudinal axial lines of these cantilever members extending in opposition to the direction of the displacement of the compressed air supply sleeve, when the latter is screwed into the nut, these cantilever members being adapted to engage an abutment of the compressed air supply sleeve, as the latter is screwed into the nut.

United States Patent Sudnishnikov et al.

[151 3,651,874 [451 Mar. 28, 1972 [54] PNEUMATICALLY OPERATED IMPACT-ACTION SELF-PROPELLED REVERSIBLE MECHANISM [72] Inventors: Boris Vasillevich Sudnishnikov, Kransy prospekt, 54, kv. 59; Alexandr Dmitrievich Kostylev, ulitsa Derzhavina, 19, kv. 44; Konstantin Stepanovich Gurkov, ulitsa Derzhavina, 19, kv. 68; Konstantin Konstantinovich Typitsin, ulitsa Krylova, 3, kv. 37; Vladimir Vasilievich Kllmashko, ulitsa Navogodnyaya, 44, kv. 23; Vladimir Dmitrievich Plavskikh, ulitsa Kamenskaya, 83 v, kv. 33, all of Novosibirsk, U.S.S.R.

[22] Filed: July 8, 1970 [21] Appl.No.: 53,216

3,407,884 10/1968 Zygmuntet al.... ..l73/91 FOREIGN PATENTS OR APPLICATIONS 1,170,167 11/1969 Great Britain ..173/91 Primary Examiner-James A. Leppink Attorney-Holman & Stern ABSTRACT There is disclosed a pneumatically operated impact-action self-propelled reversible mechanism for driving holes in the earth by compacting the soil around the hole being made, comprising a housing having a pointed end and receiving thereinside an impact member delivering successive impacts upon the housing, as this impact member is reciprocated interiorly of this housing in operation of the mechanism under the action of compressed air, the mechanism further including a compressed air supply sleeve connected with an air conduit member and threadedly secured in a nut for axial displacement relative to this nut, when the air conduit member is rotated. According to the invention, the nut, associated with the compressed air supply sleeve, has a plurality of longitudinal oblique slits made therein, these slits defining therebetween a pair of resiliently deformable cantilever members projecting axially beyond the adjacent face end of the nut, the longitudinal axial lines of these cantilever members extending in opposition to the direction of the displacement of the compressed air supply sleeve, when the latter is screwed into the nut, these cantilever members being adapted to engage an abutment of the compressed air supply sleeve, as the latter is screwed into the nut.

3 Claims, 3 Drawing Figures PATENTEDMARZB 1972 3,651,874

/ y/// //l //////j/// 3 FIE! A PNEUMATICALLY OPERATED IMPACT-ACTION SELF- PROPELLED REVERSIBLE MECHANISM The present invention relates to pneumatically operated impact-action self-propelled reversible mechanisms for driving holes in the earth by compacting the soil around the hole being made; the invention can be employed, for example, for making underground communication conduits by the socalled closed", trench-less method.

There is known from the British Pat. No. 1,170,167 and German Pat. No. 1,634,417 a pneumatically operated impactaction self-propelled mechanism for driving holes in the earth by compacting the soil around the hole being made, which comprises a housing with a pointed end, receiving thereinside a movable impact member forming with said housing a front working chamber alternatively communicating with a source of compressed air and with the ambient atmosphere, this front working chamber being formed between said housing and the external surface of said impact member, said impact member forming a rear working chamber in the rear end portion thereof this rear chamber continuously communicating with the source of compressed air. The impact member delivers successive impacts upon said housing, as this impact member is reciprocated in said housing under the action of compressed air supplied into the abovementioned working chamber through a compressed air supply sleeve, cooperating withthe impact member. This compressed air supply sleeve is secured in the end portion of the housing, opposite to the pointed end, by means of a nut, this sleeve being displaceable axially in respect of said nut, when the air supply hose, connected with the sleeve, is rotated. In this mechanism, the axial adjustment of the position of the compressed air supply sleeve relative to the nut leads to a change in the pattern of the operative distribution of the compressed air between the abovementioned working chambers of the mechanism, and, therefore, to the reversion of the direction of the impacts delivered by the impact member, and, hence-to the reversion of the motion of the mechanism, as a whole.

This reversal of the motion of the mechanism, in order to make the mechanism extracted from the hole it has already made back to the surface, might be necessary, when the mechanism meets an insurmountable obstacle, e.g., a boulder, the remnants of a foundation, etc., or else when the blind hole of a desired length has been already driven by the mechanism.

However, this known reversible mechanism has a disadvantage arising from the tendency displayed by said compressed air supply sleeve to lock itself in the abovementioned nut, as the mechanism is driven for a forward motion, this selflocking impeding, and, more often than not, positively preventing reversal of the mechanism in the hole, because it becomes impossible to unscrew the sleeve from the nut by the rotation of the compressed air supply hose, non-rotatively connected with the sleeve.

It is an object of the present invention to provide a pneumatically operated impact-action self propelled mechanism in which self-locking of the compressed air supply sleeve in the nut should be positively prevented.

This and other objects are accomplished in a pneumatically operated impact-action self-propelled reversible mechanism for driving holes in the earth by compacting the soil, comprising a housing with a pointed end, receiving thereinside a movable impact member defining with said housing working chambers of variable volume and reciprocating within said housing under the action of compressed air, said impact member delivering repeating impacts upon said housing, as a result of its reciprocations, compressed air being supplied into said chambers through an air conduit means and a compressed air supply sleeve cooperating with said impact member, said compressed air supply sleeve being connected with said air conduit means and being threadedly secured in a nut for axial displacement relative to said nut, when said air conduit means is rotated. According to the present invention, said nut, associated with said compressed air supply sleeve, has a plurality of longitudinal oblique slits made therein, said slits defining therebetween at least a pair of resiliently deformable cantilever members projecting axially beyond the adjacent face end of said nut, the longitudinal axial line of each said resiliently deformable cantilever member extending in opposition to the direction of the displacement of said compressed air supply sleeve, when the latter is screwed into said nut, said cantilever members being adapted to engage an abutment of said compressed air supply sleeve, when the latter is screwed into said nut.

According to a preferred embodiment of the present invention, said resiliently deformable cantilever members represent each a beam displaying uniform resistance in the direction of the action of friction forces produced by the engagement of said resiliently deformable cantilever members with said abutment of said compressed air supply sleeve, the angle of the inclination of the longitudinal axial line of each said cantilever member relative to the generatrix of the cylindrical surface of said nut being of a value substantially equal to the angle of friction produced by the engagement of said resiliently deformable cantilever members with said abutment of said compressed air supply sleeve, when the latter is screwed into said nut.

It is also expedient for each said resiliently deformable cantilever member to have a smooth internal surface.

As a result of the present invention, there has been provided a pneumatically operated impact-action self-propelled reversible mechanism ensuring faultless selective reversal of its motion.

The present invention will be better understood from the following detailed description of an embodiment thereof, with reference being has to the accompanying drawings wherein:

FIG. 1 is a schematic axially sectional view of a pneumatically operated impact-action self-propelled reversible mechanism, constructed in accordance with the present invention;

FIG. 2 shows the unit A ofthe FIG. 1;

FIG. 3 is a cross-sectional view taken along line Illlll of FIG. 2.

Referring now in particular to the appended drawings, there is disposed inside a hollow cylindrical housing 1 (FIG. 1) an impact member 2 engaging the internal cylindrical wall of the housing by a pair of annular projections 3 and 4, respectively.

The space inside the housing 1, defined by the internal surface of the housing 1, on the one hand, and by the external surface of the impact member 2on the other hand, constitutes the front working chamber 5.

Formed within the rear, or tail portion of the impact member 2 is a space 6 receiving therein the head (i.e., the greater diameter portion) of a compressed air supply sleeve 7. The space 6 constitutes the rear working chamber of the herein disclosed mechanism. The wall of the impact member 2 has made therein ports 8 for fluid communication between the chambers 5 and 6.

The compressed air supply sleeve 7 has its stem (i.e., the smaller diameter portion) provided with annular abutrnents 9 and 10, this stern being threadedly secured in the threaded passage of a nut 11, this nut, in its turn, being threadedly secured in the housing 1 by means of the external thread of the nut 11 engaging the internal thread of the housing 1. The nut outlet passages 12 for exhaust of air made therethrough and is provided with a pair of cantilever members 13 (FIG. 2).

The rear end portion of the compressed air supply sleeve 7 non-rotatively receives thereabout the end portion of an air supply sleeve 14 (FIGS. 1 and 20.

When the herein disclosed mechanism is set for forward motion, the compressed air supply sleeve 7 is set into its extreme forward position, its abutment 10 engaging the free ends of the resilient cantilever members 13 of the nut 11, these cantilever members being formed each in the body of the nut 11 by the respective pair of oblique slits defining this cantilever member therebetween, each cantilever member 13 having its free end portion projecting in the axial direction beyond the respective face end of the body of the nut 11. The

respective longitudinal axes of the cantilever members 13 extend toward the abutment of the sleeve 7, in a direction opposite to the motion of the latter, when it is screwed into the nut 11, whereby the free ends of the cantilever members 13 present a pair of stops for the abutment 10 of the sleeve 7, when the latter is screwed into the nut 1 l.

The cantilever members 13 act as a pair of beams displaying uniform resistance in the direction of the action of friction forces produced by engagement of the free ends of the cantilever members 13 with the annular abutment 10 of the compressed air supply sleeve 7, the angle of the inclination of the longitudinal axial line of each cantilever member 13 in respect of the generatrix of the cylindrical surface of the nut 11 being made substantially equal to the angle of friction produced by the engagement of the cantilever members 13 with the abutment 10 of the compressed air supply sleeve 7.

In order to prevent engagement between the cantilever members 13 and the external thread of the sleeve 7, the inter nal surface of each cantilever member 13 is made smooth.

When compressed air is supplied from an appropriate source (not shown) into the supply hose 14, the compressed air finds its way through the axial passage in the sleeve 7 into the rear working chamber 6, whereby the impact member (of which the communication ports are in this position cut off the rear chamber 6 by the head of the sleeve 7) is driven forward, into the chamber 5 inside the housing 1, and strikes the latter in the forward direction, and thus the housing 1 is driven forward relative to the sleeve 7.

When the impact member 2 thus moves toward its extreme forward position, i.e., the position in which it strikes the housing 1, at a certain point immediately preceding this position (the point being defined by the disposition of the communication ports 8 in the body of the impact member 2) the communication ports 8 establish communication between the front working chamber 5 and the compressed air source through the chamber 6, the passage 15 and the hose 14.

The rebound of the impact member 2 together with the action of the compressed air in the front chamber 5 are responsible for the stroke of the impact member 2 in the return, i.e., rearward direction, the working surface of the impact member 2, subjected to the action of the compressed air in the front chamber 6, being greater than the working surface of the same impact member, subjected to the action of the compressed air in the rear chamber 6 continuously communicating with the source of the compressed air.

During the return stroke of the impact member 2 the communication Ports 8 at a certain point become closed by the cylindrical external wall of the head portion of the sleeve 7, but the continuing pressure inside the chamber 5 and the momentum gained by the impact member 2 make the latter move on, against the action of the pressure of the compressed air in the chamber 6. DUring the return stroke of the impact member 2 the volume of the chamber 5 expands.

The end of the return stroke of the impact member 2 is defined by the communication ports 8 thereof passing in the rearward direction beyond the head portion of the compressed air supply sleeve 7, whereby there is established communication between the front chamber 5 and the ambient atmosphere through the exhaust passages 12 in the nut 11. In this manner the used up compressed air is exhausted.

If the supply of compressed air into the supply hose 14 is continued, the abovedescribed operating cycle repeats itself.

The reaction force produced by the return stroke of the impact member 2 in operation of the herein disclosed mechanism, which acts upon the housing 1 in the direction opposite to the desired direction of the progress of the latter, is taken up, or counterbalanced by the friction between the housing 1 and the surrounding earth, brought about byv the resilient properties of the earth.

When the herein disclosed mechanism encounters an insurmountable obstacle (a boulder, the remnants of a foundation, etc.), or when a blind hole of a desired length has been made, the motion of the mechanism can be reversed, for the mechanism to retreat under the action of the compressed air back to the surface along the hole it has already made. In order to reverse the motion of the mechanism, the compressed air supply hose 14 is temporarily disconnected from the compressed air source (not shown) and is rotated to transmit the torque to the compressed air supply sleeve 7 with which the hose 14 is connected non-rotatively. In this manner the sleeve 7 is rotated in the unscrewing direction, i.e., is unscrewed from the nut 11 into the rearmost position of the sleeve 7, in which the abutment 9 thereof engages the front face of the nut 11.

With the compressed air supply sleeve 7 being set in the last-mentioned position, the impact member during its forward stroke is stopped by the pressure of the compressed air in the front chamber 5 before it reaches the internal end wall of the housing 1, and thus delivers no impact upon the housing 1 in the forward direction. Moreover, the now increased initial volume of the front chamber 5 and the rearmost position of the head of the sleeve 7 are responsible for the impact member 2 reaching the front face of the nut 11 during the return stroke thereof and thus delivering a rearwardly directed blow upon the nut. These repeated impacts of the impact member 2 upon the nut 1] drive the entire mechanism for the retreating motion.

The reaction force produced by the forward strokes of the impact member 2 and acting upon the housing 1 in the direction opposing its retreating motion is taken up, or counterbalanced (as it has been already described in connection with the-forward motion of the mechanism) by the friction between the earth and the housing 1.

In the course of the forward motion of the herein disclosed mechanism the action of the pulse loads may bring about a tendency of the sleeve 7 to screw itself further on into the nut 11 and thus to get positively locked in this nut. This selflocking of the compressed air supply sleeve 7 in the nut 11 is prevented by the resilient cantilever members 13. After the abutment 10 of the sleeve 7 has engaged the free ends of the cantilever members 13, any further screwing of the sleeve 7 into the nut 1 1 produces a friction force between the free ends of the cantilever members 13 and the abutment 10, this friction force bending the cantilever members in the screwing direction, and the resistance of the cantilever members puts a positive limit to the self-screwing of the sleeve 7 into the nut 11.

' Now, when the motion of the herein disclosed mechanismis to be reversed, but a slight torque applied to the hose 14 in the unscrewing direction and transmitted by the hose to the sleeve 7 is assisted by the resilient deformation of the cantilever members 13, and thus the compressed air supply sleeve can be easily unscrewed into the rearmost position thereof.

A series of tests which have been carried out with a sample of the herein disclosed mechanism has proved that in this mechanism any self-locking of the air supply sleeve in the nut is positively prevented.

What is claimed is:

1. A pneumatically operated impact-action self-propelled reversible mechanism for driving holes in the earth by compacting the soil, comprising: a housing of said mechanism, having a pointed end; an impact member adapted for reciprocation interiorly of said housing and defining therewith working chambers of variable volume, said impact member delivering upon said housing repeating impacts, as said impact member is reciprocated thereinside in operation of said mechanism; an air conduit means; a sleeve connected with said air conduit means and cooperating with said impact member, said sleeve being adapted to supply compressed air into said chambers for effecting reciprocations of said impact member; a nut secured in said housing adjacent to the end thereof, opposite to said pointed end, said compressed air supply sleeve being threadedly secured in said nut for axial displacement relative to said nut, when said air conduit means is rotated; said nut having a plurality of longitudinal oblique slits made therein, said slits defining therebetween at least a pair of resiliently deformable cantilever members projecting axially beyond the adjacent face end of said nut, the longitudinal axial line of each said resiliently deformable cantilever member extending in opposition to the direction of the displacement of said compressed air supply sleeve, when the latter is screwed into said nut, said cantilever members being adapted to engage an abutment of said compressed air supply sleeve, when the latter is screwed into said nut.

2. A pneumatically operated mechanism, according to claim 1, wherein said resiliently deformable cantilever members represent each a beam displaying uniform resistance in the direction of the action of friction forces produced by the engagement of said resiliently deformable cantilever members 

1. A pneumatically operated impact-action self-propelled reversible mechanism for driving holes in the earth by compacting the soil, comprising: a housing of said mechanism, having a pointed end; an impact member adapted for reciprocation interiorly of said housing and defining therewith working chambers of variable volume, said impact member delivering upon said housing repeating impacts, as said impact member is reciprocated thereinside in operation of said mechanism; an air conduit means; a sleeve connected with said air conduit means and cooperating with said impact member, said sleeve being adapted to supply compressed air into said chambers for effecting reciprocations of said impact member; a nut secured in said housing adjacent to the end thereof, opposite to said pointed end, said compressed air supply sleeve being threadedly secured in said nut for axial displacement relative to said nut, when said air conduit means is rotated; said nut having a plurality of longitudinal oblique slits made therein, said slits defining therebetween at least a pair of resiliently deformable cantilever members projecting axially beyond the adjacent face end of said nut, the longitudinal axial line of each said resiliently deformable cantilever member extending in opposition to the direction of the displacement of said compressed air supply sleeve, when the latter is screwed into said nut, said cantilever members being adapted to engage an abutment of said compressed air supply sleeve, when the latter is screwed into said nut.
 2. A pneumatically operated mechanism, according to claim 1, wherein said resiliently deformable cantilever members represent each a beam displaying uniform resistance in the direction of the action of friction forces produced by the engagement of said resiliently deformable cantilever members with said abutment of said compressed air supply sleeve, the angle of the inclination of the longitudinal axial line of each said cantilever member relative to the generatrix of the cylindrical surface of said nut being of a value substantially equal to the angle of friction produced by the engagement of said resiliently deformable cantilever members with said abutment of said compressed air supply sleevE, when the latter is screwed into said nut.
 3. A pneumatically operated mechanism, according to claim 2, wherein said resiliently deformable cantilever members have each a smooth internal surface. 